Walk-in type coolers, such as those commonly found in convenience stores today, are typically constructed of insulated wall, ceiling and floor panels that are fastened snugly together. The panels are usually comprised of foam insulation, such as expanded polyurethane, which may be encased within thin metallic sheets. The panel ends are shaped to fit together in tongue and groove fashion and are provided with latch type fastening means for drawing and holding them snugly together. The latches themselves are commonly comprised of a hook assembly mounted to one panel for latching engagement with a pin assembly mounted to an adjacent panel. Exemplary of these latches are those shown in U.S. Pat. Nos. 3,565,469, 4,223,500 and 4,417,430. These latch type fasteners are sometimes formed in situ during formation of the insulation into the shape of blocks while others are designed to be mounted to the insulation after they have been formed into panels.
The latches used in interlocking adjacent panels together have had problems associated with their incorporation into the panels and use. For example, where the latch members have not been formed in situ as the insulation is formed into blocks, a cavity has had to be cut into the insulation to receive the hook and pin assemblies. This has been tedious and inefficient and has often resulted in an unsightly product. Regardless of the method of incorporation, their design is such that as the latch hook is rotated into gripping engagement with a latch pin of an adjacent panel, a pulling force is exerted on both the hook assembly and on the pin assembly. Though this force beneficially serves to draw the panels snugly together, it also tends to dislodge the latch assemblies from the insulation. To prevent this dislodgement anchor wings have been added to the latch assemblies which substantially extend the surface area contact of the latches with the insulation and thereby spreads out the dislodging forces. Exemplary of this type of panel fastener is again that shown in U.S. Pat. No. 4,417,430. However, even with the addition of these wings the pulling forces are sometimes so great as still to dislodge a latch assembly so as to render it ineffective.
Banded systems have been devised to overcome the just described problem and to provide enhanced integrity. With these systems opposite ends of bands or rods are welded to the latches in opposite ends or sides of the panels so that latching forces applied to one latch is also applied to another latch. Although this definitely provided a more ruggedized panel with enhanced latch dislodgement resistance, such panels are quite costly to produce.
It thus is seen that a need remains for an insulated panel that may be fastened to adjacent panels of like construction in a more secure and yet less costly manner and with little risk of their latching mechanism being dislodged during latching operations. Accordingly, it is to the provision of such a panel and method of producing such that the present invention is primarily directed